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Wei Zheng,Hong-Bin Wang,Zhi-Ming Zhang,Ning Li,Peng-Heng Yin 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.4
This paper addresses the trajectory tracking and obstacle avoidance control problems for a class ofmobile robot systems. Two classes of controllers are designed for the mobile robot system in the free motion,respectively. A new hybrid position virtual-force controller is designed to adjust the distance between the mobilerobot and the obstacles. Since the uncertainties between the mobile robot dynamics model and obstacles degradethe performance of the obstacle avoidance system, a multi-layer feed-forward neural networks (NNs) deep learningmethod with hybrid position and virtual-force is proposed, such that the distance between the mobile robot andthe obstacles converges to an adjustable bounded region. It is shown that the proposed controller in this paperis smooth, effective, and only uses the system output. The control design conditions are relaxed because of thedeveloped multi-layer feed-forward NNs deep learning compensator. The simulation results and obstacle avoidancecases are performed to show the effectiveness of the proposed method.
Li, Zheng,Zhang, Li-Juan,Zhang, Hong-Ru,Tian, Gao-Fei,Tian, Jun,Mao, Xiao-Li,Jia, Zheng-Hu,Meng, Zi-Yu,Zhao, Li-Qing,Yin, Zhi-Nan,Wu, Zhen-Zhou Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.13
Tumors have evolved numerous mechanisms by which they can escape from immune surveillance. One of these is to produce immunosuppressive cytokines. Transforming growth factor-${\beta}$(TGF-${\beta}$) is a pleiotropic cytokine with a crucial function in mediating immune suppression, especially in the tumor microenvironment. TGF-${\beta}$ produced by T cells has been demonstrated as an important factor for suppressing antitumor immune responses, but the role of tumor-derived TGF-${\beta}$ in this process is poorly understood. In this study, we demonstrated that knockdown of tumor-derived TGF-${\beta}$ using shRNA resulted in dramatically reduced tumor size, slowing tumor formation, prolonging survival rate of tumor-bearing mice and inhibiting metastasis. We revealed possible underlying mechanisms as reducing the number of myeloid-derived suppressor cells (MDSC) and $CD4^+Foxp3^+$ Treg cells, and consequently enhanced IFN-${\gamma}$ production by CTLs. Knockdown of tumor-derived TGF-${\beta}$ also significantly reduced the conversion of na$\ddot{i}$ve $CD4^+$ T cells into Treg cells in vitro. Finally, we found that knockdown of TGF-${\beta}$ suppressed cell migration, but did not change the proliferation and apoptosis of tumor cells in vitro. In summary, our study provided evidence that tumor-derived TGF-${\beta}$ is a critical factor for tumor progression and evasion of immune surveillance, and blocking tumor-derived TGF-${\beta}$ may serve as a potential therapeutic approach for cancer.
Wei Zheng,Zhi-Ming Zhang,Hong-Bin Wang,Hong-Rui Wang,Peng-Heng Yin 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.6
This paper addresses the stability analysis and dynamic output-feedback control problems for a class of nonlinear Takagi-Sugeno (T-S) fuzzy systems with multiple subsystems and normalized membership functions. First, the switching control law of the membership function is proposed based on the membership function for the nonlinear T-S fuzzy subsystems. Secondly, the relaxation parameter is introduced into this switching control law to guarantee a minimal dwell time between two consecutive switching. Then, based on the proposed switching control law of the membership function and relaxation parameter, the dynamic output feedback controller with the estimate algorithm is designed to estimate the attraction domain. By introducing the new switched Lyapunov-Krasovskii functional, it can be seen that the solutions of the resultant closed-loop system converge to an adjustable bounded region. Compared with the previous works, the developed controller in this paper is flexible and smooth, which only uses the system output. And the results are further extended to the mobile robot case and the chemical process case. Finally, two simulation examples are performed to show the effectiveness of the theoretical results.
Mei Shen,Zhi-Qiang Liu,Yu-Guo Zheng,Yin-Chu Shen 한국생물공학회 2009 Biotechnology and Bioprocess Engineering Vol.14 No.6
The medium components of nitrilase production by Arthrobacter nitroguajacolicus ZJUTB06-99 were optimized in this study. Effects of factors such as carbon sources, nitrogen sources, and inducers on nitrilase production were investigated. Glucose, yeast extract, and ε-caprolactam were chosen as the suitable components. Moreover, experiments were carried out to fix the concentration of three factors for the zero coded level of variables in the subsequent optimization. Response surface methodology (RSM) and central composite design (CCD) were employed for further optimization. A quadratic model was found to fit the nitrilase activity and the variables. The results revealed that the optimized medium contained (%, w/v) 2.80, glucose; 0.57, yeast extract; and 0.42, ε-caprolactam. Validation experiments were carried out under the optimized conditions and nitrilase activity of 107.49 U/L was close to the predicted activity 110.82 U/L. After optimization, the nitrilase activity attained 2.86 fold of activity compared to the unoptimized conditions and the conversion of acrylonitrile was significantly improved. The strain growth curve and nitrilase activity alteration in the course of culture were tested. The cells were suitably harvested after cultured for 72~78 h The medium components of nitrilase production by Arthrobacter nitroguajacolicus ZJUTB06-99 were optimized in this study. Effects of factors such as carbon sources, nitrogen sources, and inducers on nitrilase production were investigated. Glucose, yeast extract, and ε-caprolactam were chosen as the suitable components. Moreover, experiments were carried out to fix the concentration of three factors for the zero coded level of variables in the subsequent optimization. Response surface methodology (RSM) and central composite design (CCD) were employed for further optimization. A quadratic model was found to fit the nitrilase activity and the variables. The results revealed that the optimized medium contained (%, w/v) 2.80, glucose; 0.57, yeast extract; and 0.42, ε-caprolactam. Validation experiments were carried out under the optimized conditions and nitrilase activity of 107.49 U/L was close to the predicted activity 110.82 U/L. After optimization, the nitrilase activity attained 2.86 fold of activity compared to the unoptimized conditions and the conversion of acrylonitrile was significantly improved. The strain growth curve and nitrilase activity alteration in the course of culture were tested. The cells were suitably harvested after cultured for 72~78 h
Wei-hua Yin,Yan Zhang,Xiang-nan Li,Hong-yue Wang,Yun-qiang An,Yang Sun,Zhi-hui Hou,Yang Gao,Bin Lu,Zhe Zheng 대한영상의학회 2020 Korean Journal of Radiology Vol.21 No.2
Objective: We sought to distinguish lipid plaques using a CT quantitative pixel density histogram, based on the pathological diagnosis of lipid cores as the gold standard. Materials and Methods: Eight patients awaiting heart transplantation due to end-stage coronary heart disease underwent coronary CT angiography (CCTA) spectroscopy prior to heart transplantation; coronary artery pathological analysis was performed for all patients. Lipid-core plaques were defined pathologically as manifesting a lipid core diameter > 200 μm, a circumference > 60 degrees, and a cap thickness < 450 μm. The percentage distributions of CT pixel attenuation ≤ 20, 30, 40, and 50 HU were calculated using quantitative histogram analysis. Results: A total of 271 transverse sections were co-registered between CCTA and pathological analysis. Overall, 26 lipid cores and 16 fibrous plaques were identified by pathological analysis. There was no significant difference in median CT attenuation between the lipid and fibrous plaques (51 HU [interquartile range, 46–63] vs. 57 HU [interquartile range, 50–64], p = 0.659). The median percentage of CT pixel attenuation ≤ 30 HU accounted for 11% (5–17) of lipid-core plaques and 0% (0–2) of fibrous plaques (p < 0.001). The sensitivity and specificity of the method for diagnosing lipid plaques by the average CT pixel attenuation ≤ 30 HU were 80.8% and 87.5%, respectively. The area under the receiver operator characteristics curve was 0.898 (95% confidence interval: 0.765–0.970; 3.0% was the best cut-off value). The diagnostic performance was significantly higher than those of the average pixel CT attenuation percentages ≤ 20, 40, and 50 HU and the mean CT attenuation (p < 0.05). Conclusion: In in vivo conditions, with the pathological lipid core as the gold standard, quantification of the percentage of average CT pixel attenuation ≤ 30 HU in the histogram can be useful for accurate identification of lipid plaques.
Rui Qian,Yin Zheng‐Zhi,Cai Wenrong,Li Junyao,Wu Datong,Kong Yong 대한화학회 2022 Bulletin of the Korean Chemical Society Vol.43 No.5
A simple drug controlled delivery system is facilely designed for pH-responsive delivery of methotrexate (MTX), an anticancer drug. Aminated mesoporous silica nanoparticles (AMSNs) were first synthesized for the loading of MTX, and then the MTX-loaded AMSN (AMSN-MTX) was encapsulated with hyaluronic acid (HA) through electrostatic attractions. Successful preparation of the HAencapsulated AMSN-MTX (AMSN-MTX-HA) is confirmed by different characterizations such as scanning electron microscopy, Fourier transform infrared, x-ray diffraction, and so on. Because the protonation/deprotonation of HA is closely related to pH, the electrostatic interactions between HA and AMSN depend closely on the pH of the medium and thus pH-responsive delivery of MTX is achieved. The release kinetic data of MTX from the carrier fit well to Higuchi and Korsmeyer-Peppas models. Cell experiments indicate that the developed AMSN-MTX-HA displays high inhibitory effect on hepatoma (SMMC-7721) cells while the drug-free carrier of AMSN-HA has good biocompatibility.
Shen, Fang,Wu, Chun-Xiao,Yao, Yu,Peng, Peng,Qin, Zhi-Yong,Wang, Yin,Zheng, Ying,Zhou, Liang-Fu Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.12
Background: Only few epidemiological data on primary central nervous system (CNS) tumors in Shanghai have been reported. Methods: All cases of primary CNS tumors that were registered at Center for Disease Control and Prevention (CDC) were collected (1973-2007: urban Shanghai; 2003-2007: whole Shanghai city). Trends were analyzed using joinpoint analysis and rates were stratified by age, gender and region. Histological data were collected from both CDC and Huashan Hospital. Results: From 1973 to 2007, the five-year average incidence rate in urban Shanghai increased in both genders, especially in the elderly population. Joinpoint analysis showed the age-adjusted incidence rate for males increased first but then plateaued, whilst rates for females continued increasing over the 35 years. For the five-year status quo (2003-2007), rural had a higher age-adjusted incidence rate than urban populations, and females higher than males, especially those with advanced age. According to CDC (2003-2007) and Huashan Hospital (1951-2011), the two most common histological subtypes were neuroepithelial tumors (with male predominance) and meningiomas (with female predominance). Conclusions: In Shanghai, a steadily increased incidence rate of primary CNS tumors was observed in general, and in the elderly and female population in particular.